Can I add a FET in parallel to this boost circuit

DarrenB · Jul 7, 2022

I use these AliExpress boost converters to charge batteries but I would like to make it function closer to its rated specifications. At the moment it gets really hot when at around 70% of its max rated load. I have tried replacing the fan with one that has a higher static pressure rating and it helped considerably but I was thinking I could take it further by adding a larger heatsink and another FET in parallel. Is it possible to add an identical FET in parallel to this pre made boost converter? It currently uses a 055N15A but If possible I would replace it with 2x IRFP4568. I know that the total heat will equal roughly the same but I am more concerned the thermal path being larger and the heat being shared across two packages. I am a complete beginner when it comes to electronics so please forgive me if this is a stupid question.

danadak · Jul 12, 2022

DarrenB said:
I have tried reading through things like this before but each and every hurdle will spur another question. I think I need to understand the basics of electronics. Electronics is a bit like a puzzle for me where the more you learn the easier it becomes. It can also be a bit like having a missing critical part to a math equation . Understanding what the values on data sheets are and how they interact with one another would probably also help. How did you learn electronic engineering? Self taught or an education program?

Both. Became a tech first in Navy, then schooled after service.

Prior to all that lots of hobby build stuff, make mistakes, keep building. Read
everyday (literally, rarely missed a day reading for just 1 minute or hours) for last
70+ years stuff I did not understand and slowly beat into my head concepts I started
to find correlation in.

Regards, Dana.

DarrenB · Jul 18, 2022

Ok here is what I think is the gate driver. Is it ok to upgrade the mosfet? Also here are the data sheets for the 055N15A and the TK56A12N1. I have highlighted some specifications that jumped out when I was looking at them, are these values important if we are looking at gate capacitance? If it has lower capacitance but the switch time is longer is it still a good choice?

danadak · Jul 18, 2022

Gate charge calculations :

https://toshiba.semicon-storage.com/info/docget.jsp?did=59460

https://www.infineon.com/dgdl/Infineon-Use_Gate_Charge_to_Design_the_Gate_Drive_Circuit_for_Power_MOSFETs_and_IGBTs-AN-v01_00-EN.pdf?fileId=5546d46267354aa001673ba630970081

Regards, Dana.

DarrenB · Jul 18, 2022

danadak said:
Gate charge calculations :

https://toshiba.semicon-storage.com/info/docget.jsp?did=59460

https://www.infineon.com/dgdl/Infineon-Use_Gate_Charge_to_Design_the_Gate_Drive_Circuit_for_Power_MOSFETs_and_IGBTs-AN-v01_00-EN.pdf?fileId=5546d46267354aa001673ba630970081

Regards, Dana.

Thanks. My ability to understand that information stops at the Toshiba document. Could you give me your basic opinion in regards to replacing the 055N15A with the TK56A12N1? I can't go too deep with you on this subject unfortunately because I don't know anything about electronics.

danadak · Jul 18, 2022

There is no easy answer in light of lack of original design criteria used
and docs covering this. One would have to use a schematic to start,
then evaluate your requirements for load requirements.

You can save a lot of grief and be safe and reliable if you purchase a
supply that meets your needs.

Regards, Dana.

Can I add a FET in parallel to this boost circuit

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Can I add a FET in parallel to this boost circuit

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